Results of experimental studies of acoustic signals from explosions and injections of substances at heights of 120-150 km are presented. The sources were installed on MR-12 geophysical rockets. Sound receivers were located at the earth's surface under the epicenters of the explosions. It is shown that it is possible to obtain reliable ground-based recordings of acoustic signals from high-altitude explosions and injections with an energy of 5-15 kg TNT. The recorded acoustic signals have spectral maxima in a range of 5-7 Hz. For comparison, records of acoustic signals from a meteor burning at heights of 70-90 km are presented. It is experimentally established that a significant part of the initial energy of substance injections and charge explosions with energy of 5-15 kg TNT at heights of 120-150 km arrives at the ground without appreciable molecular absorption. Distinctions between experimental results and theoretical estimations of the amplitude-temporal characteristics of acoustic pulses from high-altitude explosions, indicate the necessity to realize special theoretical studies of generation and propagation of a sound in strongly rarefied media with the use of methods advanced in kinetic theory.

The results of registration of acoustic waves at long distances from explosions are presented. The possibilities of using explosions with 10(5) erg energy to sounding of fine structure of stratospheric hayers with vertical scales of 10-100 m are determined. The stability during 7 days of fine structure of acoustic pulses refracted from stratospheric heights is observed. The examples of similarity of fine structure of acoustic signals at distances of 500 km and 650 km from explosions are presented.